In servicing modern automobile and truck gasoline engines, it is often difficult to reach the spark plugs for servicing. The engine compartment is not only more crowded than in older models, but frequently little working space is available between the engine and the surrounding sheet metal fenders, firewall and radiator. There have been attempts, from time to time, to provide a tool that overcomes the difficulties of conventional sparkplug tools. For example, Wenchel, U.S. Pat. No. 2,752,811, illustrates a socket wrench with a rubber insert. The socket wrench is of necessity not double ended, and the rubber insert is surrounded by an inelastic metal wall of the spark plug socket wrench. Burrows, U.S. Pat. No. 2,832,245, shows a similar socket wrench, which, like the wrench of Wenchel has a socket wrench part that necessarily engages the flatted sides of the spark plug when the spark plug is seated in the rubber insert. Thus, with the wrenches of Wenchel and Burrows, the spark plug cannot turn relative to the rubber sleeve if the threads of the spark plug and head become crossed or jammed. Cunningham, U.S. Pat. No. 3,322,007, shows a flexible rubber-like tube, with a handle at one end, for installing and removing spark plugs. Because the tube is flexible, it does not necessarily remained aligned, particularly if it is made sufficiently long to accommodate the requirements of some modern engines. Estep et al., U.S. Pat. No. 3,397,602, is another device in which a metal tube surrounds a rubber insert. In the case of Estep, the rubber insert is only deep enough to receive the terminal part of the spark plug. Berneiser, U.S. Pat. No. 4,478,113, shows a rubber tube with a sliding metal sleeve, and a handle in one end. Cooley, Des. U.S. Pat. No. 298,006, does not explain how it works, but it appears to be a tube of undisclosed material with a handle at one end. None of the references discloses a double ended tool, nor does any of them disclose a rigidly expansible outer tube with a compressibly resilient inner lining.
Normal engine servicing requires the removal, cleaning and reinstalling or replacement of the spark plugs. Rather than removing accessories or parts, service technicians prefer to work between and around obstructions. Existing tools for removing and installing spark plugs are not well adapted for holding a spark plug as it is being removed, or for permitting a spark plug to be properly aligned for installation in such a way as to eliminate or minimize the danger of cross-threading.
In many forms of internal combustion engines the well in which the spark plug is placed is so deep that it is difficult manually to line up the plug for threading it into the hole or to grasp it for removal of the loosened plug.
One of the objects of this invention is to provide a tool that is adapted to be used in the installation and removal of spark plugs or other elongated threaded members, which is slim and compact enough to permit its use on modern, crowded, engines with deep wells.
Another object is to provide such a tool which is simple, economical to make, dependable in use, where both ends of the tool are utilized, and the external surface is color coordinated.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.